1. Field of the Invention
This invention relates generally to scan converters and more particularly to a scan converter apparatus for a video signal to provide an output video signal having a horizontal frequency different from that of an input video signal.
2. Description of the Prior Art
A scan converter apparatus has been proposed so far to provide an output video signal having a horizontal or line frequency different from that of an input video signal. Conventional scan converter apparatus is generally adapted to convert an input video signal into a video signal having a doubled (integral multiple) horizontal frequency, for example, to convert an interlaced video signal into a double-scanning non-interlaced video signal or the like.
The advent of various computers, however, causes video signals to have different line frequencies ranging, for example, from 15 kHz to 64 kHz. To reproduce the video signals having different line frequencies by a single monitor television receiver, a scan converter apparatus must be provided to convert an input video signal having an arbitrary line frequency into an output video signal of which the line frequency is selected to be a fixed value.
However, when a line frequency f.sub.H2 of an output video signal is not selected to be an integer multiple of a line frequency f.sub.H1 of an input video signal, it becomes difficult to interpolate the signal and the input video signal cannot be converted into the output video signal having a proper line frequency.